This project utilizes cardiac catheterization and/or selected noninvasive techniques to evaluate longterm function of the systemic ventricle in patients with congenital heart disease. Various indices of ventricular function including the ventricular systolic work-end diastolic pressure, ventricular end systolic pressure-volume and ventricular stress-length relations are being evaluated in these patients at rest and during increasing afterload induced by infusion of the selective alpha pressor, methoxamine. Studies during the past year have demonstrated that (1) despite satisfactory postoperative resting hemodynamics, left ventricular (LV) dysfunction can be unmasked in patients with tetralogy of Fallot (TOF) repaired after 4 years of age (2) this latent LV dysfunction was not present in TOF patients repaired prior to 2 years of age (3) the LV functions normally in patients with ventricular septal defects repaired during infancy (4) the right ventricle in dextrotransposition of the great arteries is inferior to the normal LV as systemic pump. Over the next year I shall continue to use these techniques to evaluate pre-operative and post-operative function in older patients with ventricular septal defects, atrial septal defects and other ventricular volume overloads (such as mitral regurgitation and/or aortic regurgitation). I hope to use totally noninvasive methods to serially evaluate longterm ventricular function in various patients with congenital heart disease.